Can Dogs Smell and Detect Prostate Cancer?

Dogs have long been trained to sniff out a variety of things, from bombs to drugs. In more recent years, medical scenting dogs have been trained to detect different types of cancer, including bladder, prostate, and breast cancers.¹

A number of studies have further explored how dogs may help specifically detect prostate cancer. Research published in 2021 was done by a team of scientists from the United Kingdom and the United States. The results of their study show that dogs trained to detect prostate cancer in urine samples were able to correctly identify the most aggressive forms of the condition.²

How is prostate cancer usually detected?

Currently, the standard method of screening for prostate cancer cells is by measuring the amount of prostate-specific antigen (PSA) in the blood. PSA is a protein that is made by both normal and cancerous cells in the prostate gland.³

If the test results show little to no PSA in the blood, prostate cancer may not be present. If the numbers are higher than normal, it may be a sign of prostate cancer. However, high PSA can also be triggered by other factors. The only definitive way to diagnose prostate cancer is by a biopsy.³

About 2 out of 3 men who are recommended for biopsy due to high PSA levels are found to have either no sign of prostate cancer or a slow-growing form that does not require treatment.⁴

What did the study show?

In the 2021 study, neither the dogs nor their trainers knew which urine samples were from men with prostate cancer versus men without the condition. The study combined different 3 methods to study urine samples for prostate cancer:²

• The dogs' noses
• Chemical analysis of the volatile organic compounds (VOCs) in the urine samples using artificial intelligence
• Microbial analysis of the urine samples from men undergoing biopsy for suspected prostate cancer, conducted by the researchers

The results showed that the dogs' noses correctly identified 71 percent of urine samples that were positive for prostate cancer with a Gleason score of 9. Prostate cancer with this score is the most aggressive type. The dogs also correctly ignored 73 percent of urine samples that were negative for prostate cancer and other diseases.²

These rates compare to those of PSA screening tests. Researchers say that a new screening based on a trained dog's nose could support PSA tests and improve early diagnosis. This could lead to better health outcomes for men with prostate cancer, especially those with high Gleason scores.²

What does this mean for prostate cancer screening?

The researchers say the study results show specially trained dogs may provide a more accurate, non-invasive way to identify the most aggressive form of prostate cancer.²

The researchers also hope to identify the exact compounds in the urine of men with prostate cancer that allow dogs to smell and detect it. This will allow scientists to develop electronic screening tools that mimic dogs' noses so doctors can better detect prostate cancer sooner. These improved screening methods would also reduce the number of unnecessary prostate biopsies.²